The 3-D Fourier Series Window technique yields multi-voxel spectra from spatially localized regions of predetermined shape with minimal out-of-voxel contamination. Cylindrical voxels are utilized in this particular study, with localization first demonstrated in a phantom experiment. The method is then applied in vivo to noninvasively study the transmural distribution of 31P metabolites across the left ventricular wall of the myocardium in an intact canine model; high quality spectra are obtained from 1.4 ml voxels in about 15 to 30 minutes at 9.4 Tesla in the canine chest.